1. Field of the Invention
The present invention relates to wireless communication and, more particularly, to a method and apparatus for reporting transmission power of a terminal in a wireless communication system.
2. Related Art
3rd generation partnership project (3GPP) long term evolution (LTE) is an improved version of a universal mobile telecommunication system (UMTS) and is introduced as the 3GPP release 8. The 3GPP LTE uses orthogonal frequency division multiple access (OFDMA) in a downlink, and uses single carrier-frequency division multiple access (SC-FDMA) in an uplink. The 3GPP LTE employs multiple input multiple output (MIMO) having up to four antennas. In recent years, there is an ongoing discussion on 3GPP LTE-advanced (LTE-A) that is an evolution of the 3GPP LTE.
In order to mitigate interference due to uplink transmission, transmission power of a terminal is required to be regulated. If transmission power of a terminal is too low, it is difficult for a base station (BS) to receive uplink data. If transmission power of a terminal is too high, uplink transmission may cause excessive interference to transmission of other terminals.
In order to recognize uplink transmission power of a terminal, the terminal reports power headroom to a BS. However, power headroom is merely a difference between maximum transmission power and transmission power to be used. Thus, if a terminal arbitrarily limits transmission power, a BS may not be able to accurately recognize available transmission power of the terminal.